The potential difference applied to an X-ray tube  is increased. As a result, in the emitted  radiation, 

 The minimum wavelength of X-ray is related to the applied potential by  ${\text{λ}}_{\text{min}}\text{=}\frac{\text{hc}}{\text{eV}}\text{=}\frac{\text{12420}}{\text{V}}\stackrel{\text{o}}{\text{A}}\text{.}$
Thus the minimum wavelength decreases when V is  increased. The intensity is the rate of energy flow per unit area. The energy of photons increases when V is increased. Thus, intensity also increases with an increase  in the applied potential . However, intensity of X-rays is generally controlled by the filament current. An increase in the filament current increases its temperature which in turn increases  the rate of electron emission (thermionic emissions).Thus, more number of electrons strikes the target leading to increase in number of X-ray photons.